Here in the UK, I've never seen buffalo used as a verb, so the buffalo sentence has never seemed all that clever to me.
I've always preferred the publican's complaint - "This sign is painted wrong, you missed the spaces between Dog and and, and and and Duck" - because it doesn't rely on unmarked compounds like police-police or Buffalo-buffalo no-one uses outside linguistic puzzles :)
You could tack on several more if the fragment being corrected is "...conjunctions like butandandandor..." so that they are missing spaces between but and and, and and and and, and and and and, and and and or, and commas would help immensely.
I've always preferred the publican's complaint - "This sign is painted wrong, you missed the spaces between Dog and and, and and and Duck" - because it doesn't rely on unmarked compounds like police-police or Buffalo-buffalo no-one uses outside linguistic puzzles :)